Radar Base climate

Radar Base Frost Dates and Growing Season

NOAA 1991-2020 normals for Eagle Pass 3N, 12.3 km from Radar Base, elevation 812 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Eagle Pass 3N. A median date has an even chance of a later freeze in spring, or an earlier one in fall.

The last spring freeze typically comes around February 19 and the first fall freeze around December 1, a growing season of about 287 days.

Median at 36°F
last March 2, first November 20
Median at 32°F
last February 19, first December 1
Median at 28°F
last January 31, first December 14

Last freeze in spring

The chance of a later freeze than the date shown. At 10 percent, one spring in ten still freezes after the date; planting after the 10 percent date for 32°F is the cautious choice.

Threshold10%20%30%40%50%60%70%80%90%
36°FMar 20Mar 15Mar 9Mar 5Mar 2Feb 28Feb 23Feb 19Feb 12
32°FMar 10Mar 2Feb 28Feb 23Feb 19Feb 15Feb 9Jan 31Jan 22
28°FMar 1Feb 21Feb 14Feb 7Jan 31Jan 23Jan 14Jan 5Dec 25
24°FFeb 17Feb 9Feb 1Jan 20Jan 10Jan 4Dec 30Dec 24Dec 13
20°FFeb 10Feb 1Jan 12Jan 5Dec 31Dec 28Dec 23Dec 16Dec 11
16°F–––––––––

First freeze in fall

The chance of an earlier freeze than the date shown. At 10 percent, one fall in ten freezes before the date.

Threshold10%20%30%40%50%60%70%80%90%
36°FNov 4Nov 9Nov 13Nov 17Nov 20Nov 24Nov 27Nov 30Dec 5
32°FNov 14Nov 20Nov 25Nov 29Dec 1Dec 4Dec 8Dec 14Dec 23
28°FNov 26Dec 1Dec 5Dec 10Dec 14Dec 20Dec 26Jan 3Jan 20
24°FDec 4Dec 9Dec 14Dec 21Dec 26Jan 1Jan 7Jan 20Feb 6
20°FDec 9Dec 14Dec 19Dec 24Dec 29Jan 1Jan 7Jan 23Feb 8
16°F–––––––––

Growing season length

Days between the last spring and first fall freeze at each threshold, with the chance of a season at least that long.

Threshold10%20%30%40%50%60%70%80%90%
36°F288279273267262257250244234
32°F321311301294287281275267257
28°F360347340334324317309299285
24°F365365365365358349341333320
20°F365365365365365365365364350
16°F365365365365365365365365365

How often it gets that cold

The share of years with at least one night at or below each temperature.

36°F or colder
100% of years
32°F or colder
100% of years
28°F or colder
94% of years
24°F or colder
59% of years
20°F or colder
22% of years
16°F or colder
4% of years

Degree days

A degree day is one degree of the daily mean temperature beyond a base, for one day. Heating degree days count cold (the fuel a house burns), cooling degree days heat, growing degree days the warmth a crop needs; each crop has its own base.

Heating degree days, base 65°F
1,400
Cooling degree days, base 65°F
3,339
Growing degree days, base 40°F
11,085
Growing degree days, base 45°F
9,307
Growing degree days, base 50°F
7,604
Growing degree days, base 55°F
6,023
Growing degree days, base 60°F
4,597

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January4044137
February24917219
March11095456
April23205632
May3409871
June05671,017
July06401,105
August06651,130
September1465914
October30227663
November18243326
December3974134

What this means

NOAA computes these from the daily lows at the station over 1991-2020, fitting the dates of each year's last and first freeze to a distribution, so a date can be stated at any level of risk. 36°F is a frost risk for tender plants on a clear, calm night, since the ground cools below the air above it; 32°F is a freeze; 28°F is a hard freeze that kills most annuals.

The station is 12.3 km from Radar Base. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

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Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00412679 (Eagle Pass 3N). Public domain.